Soil Science - Study Mode

[#626] The element present in the porphyrin structure of chlorophyll molecules are
Correct Answer

(D) Magnesium and nitrogen

Explanation

Solution: The element present in the porphyrin structure of chlorophyll molecules is Magnesium and nitrogen, with each molecule containing 6.7% magnesium. Nitrogen is also a component of the chlorophyll molecule, which enables the plant to capture sunlight energy by photosynthesis, driving plant growth and grain yield. Nitrogen plays a critical role within the plant to ensure energy is available when and where the plant needs it to optimize yield. Chlorophyll pigment in the leaves absorbs the sunlight that excites the electrons in the molecules, enabling them to be transferred to other molecules. Chlorophyll and magnesium are connected in this step because magnesium helps the molecule absorb light and keeps the electrons in an excited state so that they can be transferred.

[#627] Select the pair which is not correctly matched in the term of C/P ratio and Mineralization/immobilization
Correct Answer

(D) > 400 ⇔ Net immobilization of inorganic P

Explanation

Solution: Mineralization is the conversion of biomass to gaseous form, water, salts, minerals, and residual biomass, and in soil science, the elements like phosphorus are converted to available forms. Immobilization is the conversion of inorganic compounds to organic compounds by microorganisms or plants, by which it is prevented from being accessible to plants. C/P ratio is the ratio of carbon to phosphorus in soil. Now, out of the given options, > 400 ⟺ Net immobilization of inorganic P is not correctly matched.

[#628] Soils having 200 kg available K 2 O/ha will be classed as
Correct Answer

(B) Medium

Explanation

Solution: Soils having 200 kg available K 2 O per hectare will be categorized as medium . The dense clay soil has usually a high concentration of potassium, as it traps the mineral and allows it to build to highly concentrated levels. The quality or grade of potassium fertilizers is expressed as a percentage of potassium oxide (K 2 O) equivalent. The most common potassium fertilizers used in agriculture are Muriate of Potash.

[#629] Which of the following oil cakes, in addition to its manurial value, also acts as a nitrification inhibitor
Correct Answer

(C) Neem

Explanation

Solution: Among the given options, Neem oil cakes, in addition to their manurial value, also acts as a nitrification inhibitor. Neem oil cake organic manure protects plant roots from nematodes, soil grubs and termites, probably due to its residual limonoid content. It also acts as a natural fertilizer with pesticide properties. It also acts as a nitrification inhibitor as it blocks soil bacteria from converting nitrogenous compounds into nitrogen gas and prolongs the availability of nitrogen to both short-duration and long-duration crops.

[#630] Which one is White-Mica?
Correct Answer

(A) Muscovite

Explanation

Solution: Muscovite is also known as White Mica. It represents a group of dioctahedral sheet silicates which are commonly formed in low-grade metamorphic and hydrothermally altered rocks. Mica insulation is used in high-temperature and fire-resistant power cables in aluminum plants, blast furnaces, critical wiring circuits, heaters, boilers, etc.